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Freezing a tumor improves accuracy of the procedure
Cryo-assisted lumpectomy reduces recurrence
Lumpectomy has long been recognized as an effective alternative to mastectomy for many types of malignant tumors, but the use of a cryo-probe to locate and isolate small tumors promises even more benefits to surgeons and patients.
In a peer-reviewed prospective study of 24 patients to test the technology, cryo-assisted lumpectomy was shown to be more effective at removing the entire breast tumor than the current use of needle wire localization.1 A follow-up clinical study of 250 patients is under way, says Lorraine Tafra, MD, medical director of the Breast Center at Anne Arundel Medical Center in Annapolis, MD, and lead investigator in the study.
"Breast surgeons have faced a dilemma now that women are aware of early breast cancer detection efforts, and tumors are found when they are very small," she says. "When a tumor is very small, surgeons can’t feel it in the breast tissue the way we can when the tumor is larger."
When the tumor is too small to feel, a radiologist uses ultrasound to locate the tumor, then marks it with a wire inserted into the center of the tumor, Tafra says. "This process leaves a lot to be desired," she admits. In addition to the discomfort to the patient who has to undergo two procedures back to back, there is the scheduling challenge presented with the necessity for the wire placement to immediately precede the lumpectomy, she notes.
As more surgeons become accustomed to using ultrasound in the OR, some are placing the wires themselves, Tafra says. "This eliminates some of the scheduling problems, but it still leaves the surgeon guessing as to how much tissue surrounding the tumor to remove," she adds.
Cryo-assisted lumpectomy allows the surgeon to use ultrasound to insert a cryoprobe into the center of the tumor, then activate it until the tumor and a set amount of surrounding tissue is enclosed in the ice ball, says Richard Fine, MD, a breast surgeon in Marietta, GA. "The ice ball makes a nonpalpable tumor palpable and easier to remove with accuracy," he explains. Results of the pilot study showed that if more than a 6 mm ice margin is created around the tumor, then the entire tumor is removed with clean margins 94.4% of the time. This compares to a rate of clean margins of 40% to 60% when the standard wire localization is used.1
"There are different studies that say that women undergoing lumpectomy need to return to surgery anywhere from 15% to 40% of the time because not enough tissue was removed to produce a clean margin," Fine says. No matter what the actual percentage for return to surgery is, it’s clear some women have to return to the OR, he adds.
"With the cryoprobe, I can determine how much tissue surrounding the tumor I will freeze and I can easily feel the symmetrical area I am going to remove," Fine explains. That improves the chance of getting clean margins and eliminates the need for repeat surgeries, he says.
There is only one risk to the patient with the use of the cryoprobe, Fine says. "If the surgeon is freezing a tumor that is close to the skin and does not pay close attention to the growth of the ice ball, it can create frostbite on the skin," he adds.
Techniques such as injecting saline between the skin and the top of the ice ball can prevent this problem, as will diligent monitoring of the ice ball growth, he adds. Because the use of a cryoprobe is not dangerous and is used in other applications such as treatment for fibroadenomas, it can be used by surgeons now, Fine points out.
It is true that the equipment is available to surgeons now, but "there is no reimbursement currently available, so it makes it uneconomical for a physician or facility outside the clinical trials," says Scott Tremberth, director of marketing for Sanarus Medical, the Pleasanton, CA-based manufacturer of the cryoprobe for breast surgery. "We hope to have reimbursement in place in the next six months," he says.
Costs of the disposable probes, gas tanks, and other supplies will add about $1,485 to the cost of the procedure per patient, but the overall costs to the surgeon and the same-day surgery program will be reduced because of the decrease in repeat surgeries, Tremberth notes.
Tafra say she sees this technology as one more step to enhance breast cancer treatments. "Lump-ectomies make it possible for women to conserve their breasts; early detection makes it possible for smaller tumors to be found in time to remove the cancer before it spreads; and cryo-assisted lumpectomy reduces the need for repeat surgeries and improves the precision of our surgery," she says.
1. Tafra L, Smith SJ, Woodward JE, et al. Pilot trial of cryoprobe-assisted breast-conserving surgery for small ultrasound-visible cancers. Annals of Surgical Oncology 2004; 10:1,018-1,024.
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